Towards Benchmarking GNSS Algorithms on FPGA using SyDR

Abstract

Global Navigation Satellite System (GNSS) is widely used today for both positioning and timing purposes. Many distinct receiver chips are available off-the-shelf, each tailored to match various applications' requirements. Being implemented as Application-Specific Integrated Circuits, these chips provide good performance and low energy consumption but must be treated as "black boxes" by customers. This prevents modification, research in GNSS processing chain enhancement (e.g., application of Approximate Computing techniques), and designspace exploration for finding the optimal receiver implementation per each use case. In this paper, we review the development of SyDR, an open-source Software-Defined Radio oriented towards benchmarking of GNSS algorithms. Specifically, our goal is to integrate certain components of the GNSS processing chain in a Field-Programmable Gate Array and manage their operation with a Python program using the Xilinx PYNQ flow. We present the early steps of converting parts of SyDR to C, which will be later converted to Hardware Description Language descriptions using High-Level Synthesis. We demonstrate successful conversion of the tracking process and discuss benefits and drawbacks arising thereof, before outlining next steps in preparation for hardware implementation.

Hard SyDR: A Benchmarking Environment for Global Navigation Satellite System Algorithms

“…Since this conversion did not involve any significant changes in the algorithm design (i.e., the same processing functions and data types), the tracking results are exactly the same between the Python, C/C++, and FPGA implementations. Consequently, we do not present these results here but invite the interested reader to consider our previous works for more details [ 9 , 22 ]. Instead, we evaluate our hardware design using the following KPIs: resource utilization, latency, and power/energy consumption estimates.…”

“…The Hard SyDR [ 24 ] project is based on the SyDR [ 20 ] and C SyDR [ 23 ] projects (outlined in Figure 3 ), sharing their goals of implementing a modular SDR for benchmarking GNSS algorithms. While trying to minimize redundant developments, our goal is to mix programming languages to have the best of both worlds.…”

“…We first addressed this conversion in [22] by outlining our workflow for porting the computation-heavy parts of SyDR into HLS-compatible C/C++ code [23], the targeted hardware architecture, and its integration into Python using PYNQ [24]. We motivated moving from software to hardware with three potential advantages, of which this paper retains two: (1) enable the use of AxC techniques only available in hardware [10,11] and (2) provide more realistic power and energy consumption estimates.…”